Fluid-operated drilling-machine.



I L. W. GREVE.

FLUID OPERATED DRILLING MACHINE.

APPLICATION FILED NOV. 26, 1913.

Patented Feb. 23, 1915.

3 SHEETSSHEET 1.

L. W. GREVE.

FLUID OPERATED DRILLING MAGHINE.

APPLICATION FILED NOV. 26, 1913.

1,1293% Patented Feb. 23, 1915.

3 SHEETSSHEET 2.

WITNESSES 1 '7 INVENTORQ L. W. GREVE. FLUID OPERATED DRILLING MACHINE.

APPLICATION FILED NOV. 26, 1913. 1 129 34? Patented Feb. 23, 1915.

3 SHEETS-SHEBT 3.

Fag. 1/

I WITNESSES 7 INVENTOR icence.

LOUIS w. serve, or CLEVELAND, orrro, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE CLEVELAND ROCK DRILL COMPANY, or CLEVELAND, OHIO, A Conronnrron" or OHIO.

FLUID-OPERATFD DRILLING-MACHINE.

Specification of Letters Patent.

Patented Feh. as, rare.

Application filed November 26, 1913. Serial No. 803,128.

T all whom it may concern;

Be it known that I, LOUIsW. GREVE, a

I citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements Fluid-Operated Drilling-Mach'irfies, (ii which the following is a specification.

The invention relates to fluid operated drilling machines, and particularly to the type in which the rotation of the hammer piston causes the rotation of the drill steel. The invention has for, its primary objects the provision of an apparatus in which the stroke of the hammer piston can. beshortened at will to the end that the drill steel may be rotated without any impactor a reduced impactof the hammer piston in its forward stroke either upon the drill steel or end of the cylinder, thus relieving the apparatus of shock at such times and increasing its life; the provision of apparatus of the character specified in which theoperation as above indicated is controlled from the throttle valve; the provision of an apparatus wherein the air or other motive fluid is supplied through the drill steel under the conditions above specified and wherein the exhaust from the front side of the hammer piston is throttled, thus cushioning the ham mer piston and giving a larger discharge of exhaust fluid through the drill steel; and the provision of an apparatus employing a tappet or anvil in which the tappet and the means for holding the drill steel against out ward movement rotate with the hammer piston and chuck. One embodiment of the'invention is .illustrated in the accompanying drawings, wherein- Fig. 1 is a longitudinal section through a machine having my improvement; Figs. 2, 3. 4, and 5 are transverse sections on the lines HIl[, Ill-Jill, lVlV, and V-V respectively I of Fig. 1, Fig. 6 is a section through the machine on the line Vl-Vll of Fig. 1, Fig. 7 is a diagrammatic sectional view through the inlet or throttle valve 'to the admissionvalve and the hammer piston and main valve, the inlet valve being in the position for securing the short stroke of the hammer piston, Fig. 9 is a view similar to that of Fig. 8, with the inlet valve in the same position as in Fig. 8, but with the main valve and the hammer piston in their other extremes of movement, Figs. 10 and 11 are views similar to those of Figs. 8 and 9 respectively, but with the inlet or throttle valve rotated so that the hammer piston operates normally with itsfull stroke, and Fig. 12 is a section through a modified inlet valve.

Specifically considered, my apparatus comprises the usual rifle bar for securing step-by-step. rotation of the hammer piston in connection with means controlled by the throttle whereby the stroke of the hammer piston is shortened so that the drill steel is rotated without the impact of the hammer piston thereon, such operation being particularly desirable when thesteel is being withdrawn from the hole drilled. In the particular machine illustrated the short forward stroke is secured by the use of a second'kicker port in addition to the ordinary kicker port, such second kicker port being ing of the main valve and an application of fluid pressure to the front side of the hammer piston. This second kicker port is made operative from the throttle or inlet valve and when in the position to secure the action as above specified such throttle valve also partially or completely blanks the exhaust from the front side of the hammer piston, except what escapes through the drill steel,

so that. the forward movementof the hammer piston is cushioned by the relatively slow exhaust. When the throttle valve is in its normal position and the drilling op-- eration is proceeding in the usual way, such valve blanks the said second kicker port and opens the exhaust.

Referring first to the eneral arrangement of parts as illustrated 1n Figs. 1 to 6; l is the cylinder of the machine in which reciprocates the hammer piston 2, such hammer piston having its front end 3 angular in cross section as indicated in Fig. 4; 4 is the valve cylinder in which works the usual automatic valve 5; 6 is a rotary admission or throttle valve for governing the supply of fluid pressure to the machine; 7 is the anvil or tappet which receives the impact of the i tit hammer piston and transmits it the drill steel; 8 is the drill steel; 9 is. thechuck slidably but non-rotatably' engaging thedrill steel and secured to the front endof the sleeve 10; 11 is a releasable securing means providing a lost motion connection between the drill steel and the chuck and serving to limitthe outward movement of the drill steel, and 12is a rifle bar integral with the ratchet block 13, and at its front end engaging'the rifle nut 14; carried by the hammer piston.

' The ratchet block 13 is provided with a pair of pawls15and 16 held apart by means the Springs 17 g. 6,), such pawls being adapted to engage the'ratchet teeth 18 upon the interior surface of the ratchet cage 17 a which is secured against rotation. The, arrangement of the rifling on the bar'12 with respect to the nut 14; such that as the hammer piston moves to the rear from the posi tion of Fig. 1 the tendency is to turn the rifle "bar and the ratchet disk counterclockwise (Figi 6 .but this movement is prevented '25-by t e pawls 15 and 16, so that in its movement to the near the hammer piston must rotate with respect to the. rifle bar. On the reverse movement of the hammer piston,

thesleeve. 10, the chuck 9 carried thereby,

the. drill steel. 8, and the anvil! 7 located intermediate the drill steel and the front end ofthe hammer piston. This is due to the fact that the sleeve 10 is angular in cross section, interiorly, so as to fit the front end 3 of the hammer piston (Fig. 1), and the chuck 9 which is screwthreaded tothe sleeve 10 is angular in its interior cross section in order to fit the drill steel as indicated in Fig. 5 'Similarl 'the securing member 11 I rotateswith the c uck and drill steel. so that there, is no wear upon these parts due to the relative rotation. The member 11 is made of spring material so that it can be sprung into position u on both, the drill steel and 4 20.- uport the chpck, t

motlon connection betw en the drill steel and chuck, providing for the necessary Bela.

' .twe movementof the, drill steel and chuck,

the chuck, an its front end engages a groove 19 on the drill steel. The rear end of the member 11 engiiges, a reduced, neck us providin a lost due to the fact that the steel is struck and moved forward, slightly with respect to the chuck. The member 11 prevents, the accidental separat on of the drill steel and-"chuck when themachlne is being withdrawn from its work, The parts of the body of themachine are held together in any desired way, and the anvil7 and the drill steel 9 are provided with passages 21 and 22 to permit a flow of air therethrough to the end of the drill, the fit of the front end 3 of the hammer piston in the sleeve 10 being sufliciently loose .to permit the escape of air from the front side of the hammer piston to the front end of the anvil 7 and thence through the passages 21' and 22.

The admission or throttle valve 6 is constructed as indicated in Fig. 6, the valve being provided with tapering sides and a central passage 23 through which air is supplied by means of a hose connection 24. A main supply passage 24: leads through the Wall of the valve,-and when the valve is in the position illustrated in Figs. 1 and 6 communicates with the passage 25 which leads down to the central groove 26 in the valve chamber.

The arrangement of the ports andpassages, and the operation of the machine as controlled by the admission valve and the automatic main valve will best be understood by' reference to the diagrammatic views of Figs. 7 to 11. There are three positions of the admission or throttle valve, the first of which is illustrated in Fig. 7, at which time the passage 24 is out of communication with passage 25, so that there is no operation ofthe machine. The second position of the valve is illustrated in Figs. 8 and 9, in which position the supply of fluid to the machine is throttled, since the port 24 is not in full communication with the port 25, and the arrangement is such that an earl cut off of the supply of air to -the.rear sire of the hammer piston is secured, together with a choking of the exhaust from the front side of the hammer piston, so that a relatively short stroke of the hammer piston is secured without stopping the rotation of such hammer piston and the drill steel and without stopping the supply of fluid pressure through the drill steel. The third position of the admission valve is illustrated in Figs. 10 and 11, at which time the passage 24 is in full communication with the passage 25, and the arrangement 0f the ports with respect to the valve is such that the full'normal stroke of the hammer piston is secured.

Referrin to Fig. 8, the valve cylinder 4 is provide with a pair of exhaust grooves 21. and 28, the groove 27 communicating freely with the atmosphere at all times, through the passages 29 and 30, while the groove 28 communicates at all times with a chamber 31 by virtue of the passage 32. The chamber 31- communicates with the atmosphere when the valve 6 is in one position, but does not communicate with the atmosphere when the valve 6 is in the position of Fig. 8. At the opposite ends of the valve 5 are the pressure chambers 33 and 34. The chamber 33 ,is constantly supplied with pressure from the groove 26 via the passages 35 and 36, such latter passage com municating at its lower end with a groove 37 in the wall of the cylinder. The other chamber 34 is intermittently supplied with pressure to overcome the pressure in the chamber 33 and move the valve to the'left by means of a passage 38. Other grooves 39 and 40 are provided in the walls of the valve cylinder, such grooves 39 and 40 being connected to the opposite sides of the hamhem piston by means of the passages 41 and 42 respectively. A pair of what may be termed kicker ports or passages 43 and 44-.

lead from the main cylinder of the machine and operate as hereinafter described.

When the parts are in the position indicated in Fig. 8 the operation securing the short stroke of the hammer piston is as follows. A limited amount of fluid pressure such as air passes from the passage 24 to the passage 25 and thence to the rear side of the hammer piston, via the grooves 26 and 39, and the passage 41, this tending to drive the hammer forward. If a greater quantity of air is desired for this short stroke operation the valve6 can be rotated a trifle further so that the passage 24 registers full with the passage 25 as indicated in Fig. 12 and later described. At this time a part of the exhaust'upon the front side of the hammer piston flows forwardly between the outer wall of the portion 3 of the hammer piston and the interior wall of the cylinder, and thence through the passages 21 and 22 in the anvil and drill steel. At this same time exhaust through the exhaust passage 42 is prevented, since the outlet from the chamber 31, to which the exhaust groove 28 is connected, is closed, such closure being accomplished by the blanking of the passage '45 by the inlet valve 6. The lack of free exhaust from the front side of the piston therefore serves to retard its forward movement and cushion it, thus assisting in the securing of the desired short stroke. During this period the valve 5 is held in the position illustrated, by virtue of fluid pressure supplied through the passages 35 and 36 to the chamber 33. The hammer piston moves forward until it uncovers the kicker port 44, and when the admission valve 6 is in the position illustrated in Fig. 8 the port or passage 44 is placed in communication with a passage 38 by means of a groove 47 in the wall of the valve 6. Therefore when the kicker port 44 is uncovered by the hammer piston a relatively large supply of fluid pressure is applied to the chamber 34 at the right hand end of the valve 5, tending to throw it to the position of Fig. 9. The valve 5 is therefore thrown to the left after a relativelv slight the passage 41 is cut ofi' from the supply of air from the' groove 26, while atthesame time this groove 26 is placed in communication with the passage42 leading to the front side of the hammer. piston. During the backward movement of the hammer piston the air upon the rear side thereof is free to exhaust via the passage 41, the grooves 39 and 27, andthe passage 29. When the rear end of-the hammer piston passes the kicker port 44 the supply of pressure to the right hand end of the valve 5 is cut off, and the pressure supplied to the left hand of the valve through the passages 35 and 36 serves to secure the movementof the valve back to the position of Fig. 8.

It will be seen that by the foregoing arrangement the short stroke of the piston is accomplished due to the throttling of the exhaust from the front sideof the hammer be shifted slightly so that the hammer piston strikes a relatively light blow even during this short stroke. It will also be noted that the control of the kicker port 44 and of the exhaust from the front side of the hammer piston is secured by means of the inlet or throttle valve. This is the most desirable arrangement, as the entire operation is controlled from a single element, but it will be understood that this control of the exhaust and of the early cut 03 need not necessarily be secured by means of the same admission or throttle valve, but that the invention contemplates the use of any and all means for accomplishing this result.

The next position of the admission valve 6 is illustrated in Figs. 10 and 11. When the valve is in this position the operation of the machine is normal, the stroke of the hammer piston being such as to secure a maximum impact upon the anvil, and the admission of air to operate the hammer piston being a maximum. When the valve 6 is in the position indicated in Fig. 10 the kicker passage'or port utilized in securing the short stroke of the piston is blanked and has no influence upon the machine. At this time the kicker port 43 which opens into the cylinder in advance of the kicker port 44 and which in the position of the valve 6 in Figs. .8 and 9'was blanked,is now placed in communication with the .passage '38 by means of the groove 47, and the exhaust chamber 31 is placed in free communication with the atmosphere by means of .the groove 48 and passage 49. It will also be seen that the passage 24 through the Wall of the valve 6 is placed infull communicatioii with the. passage 25, so that a maximum supply of air flows to the machine.

Referring to Fig. 10, air is supplied to the rear side of the hammer piston via the passage 41 until such hammer pistonpasses the end of the kicker port 43. During this forward movement of the hammer piston there is a free exhaustfrom the frontside thereof via the passage 42, grooves 40 and 28, chamber 31, and passages 45, 48, and 49, so that there is no retardation or cushioning of the forward stroke as was the case when the valve was in the position indicated in Figs. 8 and 9. At this time the valve 5 is held in the position illustrated in Fig. 10

by reason of the constant pressure sup:

plied to the chamber 33 from the passages 35 and 36. When" the hammer piston in its forward movement passes the end of the kicker port 43 the valve 5 is shifted to the left, since a relatively high pressure is supplied through the passages 43, 47, and 38 to the right hand end of the valve 5, the pressure in the chamber 34 thus being made to overcome the pressure in the chamber 33 and move the valve to the left. When the valve 5 is shifted to the position indicated in Fig. 11 fluid pressure is supplied to the front side of the hammer piston to move the hammer piston to the right by means of the passage 42, and at this time exhaust is occurring from behind the hammer piston via the passage 41 and the grooves 39 and 27. When the hammer piston passes the port 43 the position of the valve 5 is not immediately shifted, since the pressure in the passage 36 leading to the chamber 33 is too low. This-is due to the fact that the passage 36 is in direct communication with the cylinder behind the hammer piston, and

at this time there is only a relatively low ex-.

.haust pressure in this space. The valve 5 therefore does not shift until the piston covers the groove 37, at which time the pressure in the passage36 immediately rises sufficiently to cause the shifting of the valve 5 to the right, such movement restoring the parts to the position indicated in Fig. 10.

This delayed shifting, of the valve during the rear movement of the hammer piston is desirable, since the hammer'plston during its rear movement accomplishes the work of rotating itselfand the drill steel, and must therefore have a larger supply of air than operation of the device when the valve 6 is in the position of Figs. 10 and 11 differs from that when the valve 6 is in the position of Figs.'8 and 9, in that a later cut off of air to the rear side of the hammer piston is secured, combined with a free exhaust from 1 the front side of the hammer piston, so that a maximum-impact of the hammer piston upon the anvil is secured, while on the rearward movement of the hammer piston. the operations under the two conditions are substantially the same with the exception that a slightly later cut off is secured with the valve in the position of Figs. 8 and 9, such cut off not occurring in such case until the kicker port 44 is blanked, while in the position of Figs. 10 and 11 the cut off of the supply of air during the rearward movement occurs when the hammer piston blanks the groove 37.

Fig. 12 illustrates a slightly different arrangement of parts in the valve 6 from that illustrated in Fig. 8. As heretofore pointed out, it may be desirable to give the machine a. full supply of air even during the short stroke, and in that case the passage 24 is made to register full with the passage 25 instead bf registering only in part as indicated in Fig. 8. This is accomplished by giving the valve a little further rotation in a .front side of the hammer piston occur during the short stroke, and in that case the additional groove 50 in the wall of the valve may be provided. This groove connects the passages 45 and 49 when the valve is in the position of Fig. 12, thus permitting a choked exhaust from the front side of the hammer piston through passages 45, 50, and 49. Otherwise the valve of Fig. 12 is substantially the same as that of Fig. 8 both in construction and mode'of operation.

What I claim is:

1. Iii combination in a fluid operated drilling machine, a hammer piston, means coiiperating therewith whereby thepiston is rotated as it moves in one direction, a drill steel rotated by the rotation of the hammer piston, and means whereby the forward stroke of the hammer piston may be short- (med.

2. In combination in a fluid operated drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a drill steel rotated by the rotation of the hammer piston. and fluid pressure means for checking' and shortening the forward movement of the hammer piston, whereby the impact upon the drill steel is 'relieved'while the reciprocation of the hammer piston and the rotation thereof and of the drill steel are continued.

3. In combination in a fluid operated drilling machine, an admission valve for controlling the supply of fluid thereto, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a drill steel rotated by the rotation of the hammer piston, a means controlled by the said admissionvalve whereby the forward movement of the hammer piston is made shorter than its normal movement and the impact upon the drill steel relieved, while the rotation of the drill steel and hammer piston are continued.

4. In combination in. a fluid operated drilling machine, an admission valve for controlling the supply of fluid thereto, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a drill steel rotated by the rotation of the hammer piston, a means controlled by the admission valve whereby the forward movement of the hammer piston is made so much shorter than its normal movement that impact at its for,

ward extremity of movement is eliminated While the rotation of the drill steel and hammer piston are continued.

5. In combination in a fluid operated drilling machine, an admission valve for controlling the supply of fluid thereto, a

hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a drill steel rotated by the rotation of the hammer piston, and means whereby the exhaust from the front side of the hammer piston may be throttled so that the forward movement of said hammer piston is retarded and the impact upon the drill steel relieved.

6. In combination in a fluid operated drilling machine, an admission valve for controlling the supply offluid thereto, a hammer piston, means cooperating therewith whereby the plston is rotated as it moves in one direction, a drill steel rotated by the rotation of the hammer piston, and means controlled by the said admission valve whereby the exhaust from the front side of the hammer piston may be throttled so that the forward movement of said hammer piston is retarded and the impact -upon the drill steel relieved.

7. In combination in a fluid operated drilling machine, an admission valve for controlling the supply of fluid thereto, ,a hammer piston, means cooperating there: with whereby the piston is rotated as it moves in one direction, a drill steel rotated by the rotation of the hammer piston, and means whereby the supply of fluid pressure to the rear end of the hammer piston isreduced and the exhaust from the front side thereof is throttled, thus checking" the forwardmovement of the hammer piston and relieving the impact upon the drill steel while the reciprocation of the hammer piston and its rotation and that of the drill moves in one direction, a drill steel rotated by the rotation of the hammer piston, and means controlled by the said admission valve whereby the supply of fluid pressure to the rear end of the hammer piston .is reduced and the exhaust from the front side thereof is throttled, thus checking the forward movement of the hammer piston and relieving the impact upon the drill steel while the reciprocation of the hammer piston and its rotation and that of the drill steel are continued.

9. In combination in a fluid operated drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves. in one direction, a hollow drill steel having its passage in communication with the space on the front side of the hammer piston and arranged so as to be rotated by the rotation of the hammer piston, and means whereby the forward stroke of the hammer piston may be shortened to relieve the impact upon the drill steel, while still permitting a rotation of the hammer piston and drill steel and flow of fluid pressure through said drill steel.

10. In combination in a fluid operated. drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a hollow drill steel having its passage in communication with the space on the front side of the hammer piston and arranged so as to be rotated by the rotation of the hammer piston, and fluid controlled means whereby the forward stroke of the hammer piston may be shortened to relieve the impact upon the drill steel, While still permitting a rotation of the hammer piston and drill steel andlflow of fluid pressure through said drill stee 11. In combination in a fluid operated drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a hollow drill steel having its passage in communication with the space on the front side of the hammer piston andarranged so as to be rotated by the rotation of the hammer piston, the supply of fluid to the machine, and means controlled by said valve whereby the exhaust from the front side. of the hammer piston is throttled, ,thus shortening the forward stroke of the hammer piston, and relieving the impact upon the drill steel while still permitting a rotation of the hammer piston and drill steel and a flow of fluid through the drill steel. a, p t

12. In combination in a fluid operated drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in .one direction, a hollow drill steel having its passage in communication with the spaceon the front side of the drill steel and arranged so as to be rotated by the rotation of the hammer piston, an admission valve controlling the supply of fluid .to .the machine, and means controlled bysaid valve whereby the exhaust from ,the front side of the hammer piston is throttled'and the supply to the rear side reduced, thus shortening the forward stroke of the hammer piston and relieving the impact upon the drill steel while still permitting a rotation of the hammer piston and drill steel and a flow of fluid through the drill steel.

13. In combination in; a fluid operated drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a drill steel rotated by the rotation ofjthe hammer piston, a main valve automatically controlling the admission of' fluid pressure to the opposite ends of the hammer piston, a pair of kicker ports uncovered successively on the forward movement of the hammer piston, and adapted when uncovere to cause the shifting of the said main valve to cutoff the supply of fluid pressure behind the piston, and controlling means for blanking one of said ports so that the piston will be controlled by the other port and either make a long stroke and cause an impact-upon the drill steel or else make a short stroke in which the impact upon the drill steel is relieved.

14:. In combination in a fluid operated drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a

' drill steel rotated by the rotation of the hammer piston, a, main valve automatically controlling the admission of fluid pressure to the o posite ends of the hammer piston, a pair 0 kicker ports uncovered successively on the forward movement of the hammer piston, and adapted when uncovered to cause the shifting of the said main valve to cut oil' the supply of fluid pressure behind the piston, and controlling means for blankingone of said ports so that the piston will be controlled; by the other port and either make a long stroke and cause an impact upon the drill steel or else make a short stroke in which the impact upon the drill steel is relieved, the said controlling means in such latter case also throttling the exhaust from the front side of the hammer piston.

.15. In, combination in a fluid operated drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a drill steel rotated by the rotation of the hammer piston, a main valve automatically controlling the admission of fluid pressure to the opposite ends of the hammer piston, a pair. of. kicker ports uncovered successively on the forward movement of the hammer piston, andadapted when uncovered to cause the shifting of the said main valve to cutoff the supply of fluid pressure behind the piston, and a controlling valve which in one position will blank the rear kicker port and leave the exhaust from the front side of the hammer piston open, and which in another position will leave the said rear kicker port open and throttle the exhaust from the front side of the hammer piston, thus limiting its stroke andrelieving the impact of the'piston on its forward stroke.

16. In combination in a fluid operated drilling machine, a hammer piston, means cooperating therewith whereby the piston is rotated as it moves in one direction, a

drill steel rotated by the rotation of the hammer piston, a main valve automatically controlling the admission of fluid pressure to opposite ends of the hammer piston, a pair, of kicker ports uncovered successively one the forward movement of the hammer piston, and adapted when uncovered to cause the shifting of the said main valve to cut off the supply of fluid pressure behind the piston, and an admission valve for governing the supply of fluid to the machine, such valve in one position blanking the front kicker port and leaving the exhaust from the front side of the hammer piston open, and in another position throttling the rear kicker port.

17. In combination in a fluid operated drilling machine, a hammer piston, means cooperating therewith-whereby the piston is rotated as it-moves in one direction, a drill steel rotated by the rotation of the hammer piston, a main valve automatically controlling the admission of fluid pressure to the opposite ends of the hammer piston, a pair of kicker ports uncovered successively on the forward movement of the hammer piston, and adapted when uncovered to cause the shifting of the said main valve to cut off the supply of fluid pressure behind the piston, and an admission valve for governing the supply of fluid to the machine, such valve in one position blanking the front kicker port and leaving the exhaust from the front side of the hammer piston open, and in another position throttling the rear kicker port, the said admission valve being adapted in ,such latter position to admit a smaller supply of fluid to the machine than in the first mentioned position.

governing the application of fluidpressure alternately to the opposite ends of the hammer piston, an admission valve controlling the admission of fluid pressure to the machine, and connections governed by the admission valve whereby the length of time which fluid pressure is applied to the rear side of the hammer piston may be varied and whereby in one position the exhaust from the front side of the hammer piston is throttled.

19. In combination in a fluid operated machine, a hammer piston, automatic means governing the application-of fluid pressure alternately to the opposite ends of the ham: mer piston, an admission valve controlling the admission offluid pressure to the machine, and connections governed by the admission valve whereby the length of time which fluid pressure is applied to the rear side of the hammer piston may be varied and whereby in one position the ex 'haust from the front side-of the hammer 18. In combination in a fluid operated machine, a hammer piston, automatic means piston is throttled, said connections including a pair of kicker ports one in advance of the other over which the hammer piston passes.

20. In combination in a fluid operated machine, a hammer piston, automatic means governing the application of fluid pressure alternately to the opposite ends of. the. hammer piston and comprising a reciprocating main valve to which pressure-is applied continuously to move it in one direction, an admission valve, and connections governed by the admission valve whereby the length of time which the main valve is in position to admit fluid pressure to the rear side of the hammer piston may be varied, said connections including a pair of kicker ports one in advance of the other over which the hammer piston passes and adapted when uncovered to move the main valve in the reverse direction and cut ofl the supply of fluid pressure to the rear of the hammer piston.

In testimony whereof I have hereunto signed my name in the presence of the two subscribed witnesses.

a LOUIS W. GRE'VE. Witnesses:

J. DE Moor, H. T. Cover. 

